kwongj@caldwr.UUCP (James Kwong) (12/09/88)
Could someone please tell me how long it would take the Workstation Solution 8mm tape unit to back up 2.3 gbytes. Also what would be the comparative time on a 1600 bpi 9 tracks tape unit. E-mail reply would be fine. Thank your in advance -- James Kwong Calif. Depart. of H2O Resources, Sacramento, CA 95802 caldwr!kwongj@ucdavis.edu(Internet) ...!ucbvax!ucdavis!caldwr!kwongj (UUCP) The opinions expressed above are mine, not those of the State of California or the California Department of Water Resources.
krowitz@RICHTER.MIT.EDU (David Krowitz) (12/09/88)
We're finding that our 6250 BPI Kennedy 9400 (45 inches/sec) will backup about 150 MB/hour. The drive is attached to a 1.5MB DSP80. We are evaluating one of the Workstation Solutions' drives attached to a 4MB DN3000, and it seems to be running about 120 MB/hour. These figures are for doing full backups with WBAK. While the Kennedy 9400 can write 1600 BPI tapes at 75 inches/sec, the number of tapes needed to back up 2.3 GB would be prohibitive -- almost 60 tapes. -- David Krowitz krowitz@richter.mit.edu (18.83.0.109) krowitz%richter@eddie.mit.edu krowitz%richter@athena.mit.edu krowitz%richter.mit.edu@mitvma.bitnet (in order of decreasing preference)
dbfunk@ICAEN.UIOWA.EDU (David B. Funk) (12/10/88)
WRT posting <423@caldwr.UUCP> from kwongj%caldwr.uucp@ucdavis.ucdavis.edu (James Kwong) > Could someone please tell me how long it would take the > Workstation Solution 8mm tape unit to back up 2.3 gbytes. We find that our W.S. exatape runs at 200 megabytes / hour, average, using regular wbak on a full backup. We have it connected to an 8MB DN4000. The exact rate will depend upon the speed of the nodes that the disks are attached to and the network load. When we used a CDC Keystone tape drive (MSD6250) we got 120 MB /hour average, with regular wbak, and 200 MB /hour using W.S. tbs_wbak in interleaved mode. I would imagine that a 1600 BPI would be comparable for speed, if you could swap tapes fast enough to keep it busy. We've not tried W.S. tbs_wbak on the exatape yet, but I would expect it to be even faster. Dave Funk University of Iowa
crgabb@sdrc.UUCP (Rob Gabbard) (12/11/88)
In article <8812091434.AA04668@richter.mit.edu>, krowitz@RICHTER.MIT.EDU (David Krowitz) writes: > one of the Workstation Solutions' drives attached to a 4MB DN3000, and it > seems to be running about 120 MB/hour. These figures are for doing full If I remember right - isn't the sustained rate of the Workstation Solutions drive slower on a DN3000 than on a DN4000 ? Its got something to do with the bus. I believe the 120mb/hr is just about right on the nose of the figure on Workstation Solutions pamphlet while on a DN4000 it hits 150mb/hr (the same as the Kennedy). I don't have the pamphlet with me - or I may be be getting it confused with the figures on the Danford Exabyte which is basically the same thing. -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Rob Gabbard (uunet!sdrc!crgabb) _ /| Workstation Systems Programmer \'o.O' Structural Dynamics Research Corporation =(___)= U =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=